Process of manufacturing leading-in terminals.



PATENTBD JULY 3, 1906.

A. C. HYDE. PROCESS OF MANUFACTURING LEADING IN TERMINALS.

APPLICATION FILED APR-10y 1905.

Us-nan ST T-as PATENT omen-i.

AUGUS'IUS criARLE's HYDE, OF EALING, ENGLAND, ASSIGNORIOF ONE .HALF 'IQ KENNETH RAYDONv SWAN, OF HOLLAND PARK, ENGLAND.

Pnocsss or MANUFACTURING LEADING-IN, TERMINALS.

Specification of Letters Patent.

I Patented @1198, 1906.

, A hicaaon and April 10. 1905. Serial No. 254,881.

To all whom/ it may concern.-

Be it known that I, AUGUSTUS CHARLES HYDE, electrical engineer, a subject of the King of Great Britain and Ireland, residing at 3 Queens Gardens, Eaiing, in the county of Middlesex, En land, have invented certain new and usefu Improvements in Processes of Manufacturing Leading-In Terminals, of which thefollowlng is a specification.

In the manufacture of incandescent electric lamps and analo ous vessels requiring conductors to be led t ereinto and a highvacuum to be retained therein platinum has hitherto been the only conductor that could be satisfactorily sealed into the glass so as to make an air-tight joint.

Various attempts have been made to provide an economical substitute for latinum for this purpose. substitute shall have a coefficient of ex ansion so nearly that of the glass into w 'ch 0 en to serious objections.

it is to be sealed that when sealed into the glass of incandescent electric-lamp bulbs or analogous vessels an air-tight joint will be formed sufficient to maintain the re uired vacuum, and cracking of the glass wil not take place. It is known, for example, that alloys of nickel with iron, (sometimes called nickel-steels) and especially those consisting of either twenty-five per cent. of nickel and seventy-five per cent. of iron or of fortythree per cent. of nickel and fifty-seven per cent. of iron, have a coeflicient of expansion such that conductors made of the said alloys can be sealed into glass without the glass cracking or the conductors contractin but the use of these alloys in place of platinum is One objection is t at unless. special precautions, which are expensive and troublesome, be taken a film of oxid is formed on the surface of the nickeliron alloy while it is "being, sealed into the glass, and this film revents the close adhe- 'sion of the glass to t e metallic surface of the conductor and allows air to permeate between the said metallic surface and the glass, so that the necessary vacuum is not retained. Another objection to the use of such alloys is that frothing of the glass, due to the evolution of gases occluded in the conductor, is liable further to impair the air-tight character "of the joints. For these reasons the u e of conductors formed of such alloys has It is essential t at such I not been successful in practice in making joints which are required to be sufliciently tight to prevent leakage and retain a vacuum, the liability to leakage beingtoo gre'at toview to overcome the objection ue to oxidation. For example, it has been roposed to'coversuch conductors with a pre immary coating of glass .applied in vacuo, (see Caro- -la'ns specification of British Letters Patent ,No. 18,255, A. D. 1903,) and it has been proposed .to cover such conductors'with a tube or sheath of non-oxidizable metal or alloy, (see Thoms specification of British Letters Patent No. 908, A. D. 1890;) but as far as I am aware neither of such means has resulted in the production commercially of a satisfactory substitute for platinum as a-conductor.

My invention has for its object to overcome these difficulties and to produce an entirely satisfactory and commercially available substitute for platinumas a conductor for the purposes aforesaid, and I effect this. by the following means: I have discovered that hydro en affects in a remarkable manner the behavlor of certain metals and alloys (notably alloys of the platinum roup) when molten. I have found that hydrogen promotes the li uidity and mobility of the molten metal or alloy and that in the case of a molten alloy hydrogen enables a larger proportion of the more refractory metal to be used in the alloy than can be used at the same temperature without the mediation of hydrogen, and I have found that in coating a solid metal or alloy with a molten metal or alloy the hydrogen plays the part of a gaseous flux, its action being such that the metal or alloy to be coated is, as it were, wetted by the molten metal or alloy, producing an effect somewhat analogous to that brought about by ordinary fluxes in what is technically known as tinning. I have also found that hydrogen has the property of cleansing or freeing from 00- cluded gases certain metals or alloys-such, for example, as the aforesaid nickel-iron alloys-and that the difliculty hereinbefore mentioned, due to the evolution of occluded ases while sealing in the conductors, can e overcome by heating the said nickel-iron nickel-iron alloy with a non-oxidizahle metal 01' alloy 1 have found that if I dip a wire or the like of 11i0kel-iron alloy 11110 a su1table. molten'nonmxidizable metal or alloy 111 an atmosphere of hydrogen the 0o11du0t0r produeed possesses not only a coellicient of 0x pansion the same as or approximating to that of the glass into which it is to be sealed, but that the said eonduetor possesses all the essential qualities of platinum for hermetically sealing into glass. I would here observe that in this specification and also in the claims .when I refer to a non-oxidizable metal or alloy I mean a metal or alloy which will not be oxidized under the conditions pertaining to the sealing of the conductors into glass.

The non-oxidizalfle 0oat-ing I prefer is one 0onsisting of an alloy of silver and platinum such that its 11-1elting-point is sulli ciently lower than that of the nickel-iron alloy to al low of wires or the like of such nickel-iron alloy being immersed. in a molten bath ofthe .non-oxidizable alloy without the nickel iron alloy being melted. the composition which I find-most suitablebeing an alloy containing from thirty per cent. to fifty per cent. of platinum. I may coat the 0ondu0torsof nickeliron alloy by introducing them in suitable lengths into a molten bath of the non-oxidizable coating metal or alloy contained in a crucible or equivalent vessel heated in any suitable manner which will keep the bath in the requisite molten eondition or Inlay pass continuous lengths of the conductor through the said molten bat-h, an atmosphere of hydrogen being maintained in any case in the said crucible or equivalent vessel containing the molten bath during the 0oating operation. I may, for example, in-coating a continuous length of conductor cause the wire or the like to pass from a reel through a suitable opening or passage and under the curved lower end of a guide of any suitable hard and highly-relra0tory material, suchas porcelain or the like, the said guide being mounted so that it can be conveniently raised and lowered, in the molten bath. The wire or the like after pasing through the molten bath is led through a suitable opening or passage out of the 0rucible or vessel containing the bath and may be wound on a receiving-reel. The hydrogen can be admitted as required by a passage and opening or openings in the upper partof the crucible or vessel Containing the molten bath or through passages made in the a foresaid refractory guide under suilicient pressure to maintain an atmosphere of hydrogen in-' the space above the molten bath and also, if; desired, in the passages through which the w1re or the like is led into and j from the said crucible or equivalent vessel,

a ndcthe hydrogen can be withdrawn as desired by any suitable outlet, opening, and

passage, or it maybe burned t-hereat, provided that an atmosphere of hydrogen be 111ai11- tained in the crucible or analogous vessel. 1 h

The thickness of coatingapplied to the glass such as to render the said coated conductor'a commercially and practically satisfactory substitute for platinum for the aforesaid purposes. 1

The coating 0 eration in an atmosphere "of hydrogen, as a oresaid, may be depended upon to cleanse the wire or the like from occ uded gases or the wire or the like can be previously treated to remove the said occluded gas (for example, by previously heating the said wire or the like in an atmosphere of hydrogen) and afterward be passed through the molten coating-bath in an atmosphere of hydrogen, as aforesaid.

The accompanying drawing represents in elevation, partly in section, an apparatus suitable for use in carrying out my invention;

but is is only given as an example, and the invention is not limited to the use of such apparatus.

A is a reel carrying the wire B to be coated, and C is a reel to receive the wire when coated.

D is a guide of refractory material, round a groove in the lower curved end of which the wire B passes. The said wire can be guided by rolls E and passed through an opening f in the cover of the Vessel F, containing the molten bath F and out through the opening at the other side. The vessel F is supported in a furnace G, which may be heated by any suitable means, such as electricity, or a gas-and-air blowpipe arrangement, as illustrated.

H is a'pipc by which hydrogen is admitted to the Vessel F above the molten bath therein.

I is an outlet-pi e at which escaping hydro gen can be burned? Having now particularly described and ascertained the 'nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. The rocess of manufacturing leadingin termina s for electric-lamp bulbs and other glass vessels, which consists in coating an oxidizable metallic conductor, having substantially the same coefiicient of expansion as glass, by applying thereto a molten non-oxidizable metal, or alloy, beneath an atmosphere of hydrogen through which the conductor passes before entering the said molten metal, or alloy.

2. The rocess of manufacturing leadingin termina s for electric-lamp bulbs and other glass vessels, which consists in coating a conductor of a nickel-iron alloy, having substantially the same coefficient of expansion as glass, by applying thereto a molten non-oxidizable metal, or alloy, beneath an atmosphere of hydrogen through which the conduc tor passes before entering the said molten metal, or alloy.

'3. The rocess of manufacturing leadingin termina s for electric-lamp bulbs and other glass vessels, which consists in coating a conductor of a nickel-iron alloy, having substam tially the same coeflicient of expansion as glass, by applying thereto a molten alloy of silver and platinum, beneath an atmosphere of hydrogen through which the conductor passes before entering the said molten alloy.

4. The rocess of manufacturing leadingin termina s for electric-lamp bulbs and other glass Vessels, which consists in coating an oxidizable metallic conductor having substantially the same coefficient of expansion as glass, by appl ing thereto a molten non-oxidizable metal or alloy, beneath an atmosphere of hydrogen through which gas the conductor passes before and after the application thereto of the non-oxidizable metal or alloy.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

' AUGUSTUS CHARLES IIYDE.

Vitnesses:

KENNETH RAYDON SWAN, FREDK. L. RAND. 

